ML17347A969

LER 89-002-00:on 890116,normal Plant Cooldown Initiated Due to Small Boundary Leak of Rcs.Caused by Transgranular Stress Corrosion Cracking in Mapping Sys Thimble Guide Tube J-12 & J-7.Guide Tubes Involved Repaired or replaced.W/890214 Ltr

ML17347A969
Person / Time
Site:	Turkey Point
Issue date:	02/14/1989
From:	Conway W, Lyons E FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-89-50, LER-89-002, NUDOCS 8902220046
Download: ML17347A969 (10)

Text

gCCELEMTED DlSJBl.TlON DEMONSTR+10N v REGULATORY INFORMATION DISTRIBUTION SYSTEM SY>TE>>>(RZDS)DEACCESSION NBR:8902220046 DOC.DATE: 89/02/14 NOTARIZED:

NO FACIL:50-250 Turkey Point Plant, Unit 3, Florida Power and Light C AUTH.NAME AUTHOR AFFILIATION LYONS,E.Florida Power&Light Co.CONWAY,W.'F.

Florida Power&Light Co.RECIP.NAME RECIPIENT AFFILIATION 1 DOCKET g 05000250

SUBJECT:

LER 89-002-00:on 890116,reactor cooldown required by TS due to small unisolable leak of RCS at seal table.W/8 ltr.DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE: TITLE: 50.73 Licensee Event Report (LER), Incident Rpt, etc.NOTES RECIPIENT ID CODE/NAME PD2-2 LA EDISON,G INTERNAL: ACRS MICHELSON ACRS WYLIE AEOD/DSP/TPAB ARM/DCTS/DAB NRR/DEST/ADE 8H NRR/DEST/CEB 8H NRR/DEST/ICSB 7 NRR/DEST/MTB 9H NRR/DEST/RSB 8E NRR/DLPQ/HFB 10 NRR/DOEA/EAB 11 NRR/DREP/RPB 10 NUDOCS-ABSTRACT RES/DSIR/EIB RGN2 FILE 01 EXTERNAL: EG&G WILLIAMS,S H ST LOBBY WARD NRC PDR NSZC MAYS,G COPIES LTTR ENCL 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 1 1 1 1 1 1 4 4 1 1 1 1 1 1 RECIPIENT ZD CODE/NAME PD2-2 PD ACRS MOELLER AEOD/DOA AEOD/ROAB/DSP DEDRO NRR/DEST/ADS 7E NRR/DEST/ESB 8D NRR/DEST/MEB 9H NRR/DEST/PSB 8D NRR/DEST/SGB 8D NRR/DLPQ/QAB 10 NRR/DREP/RAB 10~NRR/TS/IB 9A 02 RES/DSR/PRAB FORD BLDG HOY,A LPDR NSIC HARRIS,J COPIES LTTR ENCL 1 1 2 2 1 1 2 2 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 D R I NZE'IO ALL"RIDS" RECIPZEÃIS:

PIZASE HELP US IO REXXJCE WASTE!CXNI'ACr'IHE DOCUK&l'XÃZ5QL DESK, ROOM Pl-37 (EXT.20079)TO EIZtGZLTE KSR NAME FKH DISTK03UTIGN LISTS FOR DOCUMEXIS YOU DON'T NEED)TOTAL NUMBER OF COPIES REQUIRED: LTTR 45 ENCL 44 "I 4 NRC Form 355 (9 53)LICENSEE EVENT REPORT (LER)U.S.NUCLEAR REGULATORY COMMISSION APPAOVED OMS NO.3)9)4104 EXPIRES: 5/31/CS FACILITY NAME (II DOCKET NUMSEA LT)PA Turkey Point Unit 3 ()5 0 0 0 5 0]pF 0""'"'Reactor Cooldown Required y ec naca peel>ca sons ue o Unisolable Leak of Reactor Coolant System at Seal Table EVENT DATE IS>LER NUMSER IS)REPORT DATE (7)OTHER FACILITIES INVOLVED (5)MONTH OAY YEAR YEAR CCQUCNTIAL NUMCCil ri c v Iororr fr UM 4 C rr MONTH OAY YEAR FACILtrr NAMES Turkey Point Unit 4 DOCKET NUMBER(SI 0 5 0 0 0 2 5 0 1 16 89 0 0 2 0 2 14 8 9 0 5 0 0 0 OPERATINO MOOS (~I POWER LEYEL 0 0 0 THIS REPORT IS SUSMI'TTED PURSUANT T 50.73(cl(2)

INI 50.73(c)(2)(r)50.73(e)(2)(r4)50.73(ell2)(r4))(AI 50.73(cl (2l (r)4)l~I 50.73(el(2)(cl 20.405(~I 50.35(cl(1) 50.35(cl(2) 50.73(el(2)(il 50.73(c I (2)I 4)50.73(ell2)

()4)20.402(4 I 20.405(~)(Ill)I 20.405(c)(IIISI 20.405(el(1)(i4)20.405(cl(1)(ir) 20.405 (el(I I (r)LICEIISEE CONTACT FOR THIS LER l12l 0 THE R EOUIREM EATS OF 10 cFR (): Icntcl one or more ol tne foriowinof l11)73.71(III 73.7)(c)OTHER ISpecify ln Aprtiect priow emf in Tert.Hl)C Form 3554)NAME AAEA CODE TELEPHONE NVMSEA Edward Lyons, Compliance Engineer COMPLETE ONE LINE FOII EACH COMPONENT FAILUAE OESCRI~ED IN THIS REPORT (13)0 5 2 6-6 7 3 1 CAUSE SYSTEM COMPONENT MANVFAC.TURER EPORTASLE'TO NPROS CAUSE SYSTEM COMPONEICT'ANUFAC TURER EPORTASL TO iroAOS A B TBG M120"'"c."o':1;/~AX SUPPLEMENTAL REPORT EXPECTED (14)YES llf YM.compirto EXPECTED SVSCIISSIOfl OA TEI NO ASSTRACT ILimit ro 1400 rpecer, I.e..eppfornmeteiy fifteen rincierpecr typewrinen finer)(14)MONTH OAY YEAR EXPECTED SUSMISSION DATE (I SI On January 16, 1989, at 1915, with Unit 3 in Hot Standby (mode 3, 547F,"'325 psig)and Unit 4 defueled, a normal cooldown of Unit 3 was initiated due to a small pressure boundary leak of the Reactor Coolant System (RCS).The leak was identified while performing an overpressure leak test of the RCS.The leak (approximately 12 drops per minute)was emanating from a crack in the flux mapping system thimble guide tube J-12.In addition, weepage was evident from guide tube J-7 ands and from the high pressure seal at E-5.Unit 3 reached cold shutdown at 1050 on January 17, 1989.Liquid penetrant (PT)examination was performed on all of the guide tubes above the seal table for both Unit 3 and 4.These examinations identified several other indications

.All of the guide tubes with unacceptable indications have been repaired or replaced.Two'uide tube segments that were replaced were sent to an offsite materials laboratory.

Based on the evaluations performed, it was concluded that the two cracks in those guide tubes were caused by transgranular stress corrosion cracking.The defects ,initiated from the outer surface of the tubes.FPL will reinspect the Unit 3 and 4 guide tubes using PT.This reinspection will be performed for Unit 3 during its next refueling outage and for Unit 4 during its next refueling outage.NRC Form 355 (9 53 I 220046 877()214 F DR ADOCI 0~00()z v F'DC~

NRC FoIIII 388A (NI3 I LICENSEE Ei T REPORT (LER)TEXT CONTINUAT N DOCRET NUMSER l2l LER NUMBER (Sl APPROVED OMS NO, 3I SOW!OS EXPIRESI 8/31/88 PAGE IS)U.S.NUCLEAR REGULATORY COMMISSION FACILITY NAME III Turkey Point Unit 3 YEAR SEGUENTIAL NUMSER REVISION NUMSER TEXT/I/ms/s spsss is/PEI/dsd, IISs sdd/ddIN///RC Form 38/IA's/Ill)o s o o o 2 5 8 9 002 0 0 0 2 OF 0 4 DESCRIPTION OF THE EVENT On January 16, 1989, at 1915, with Unit 3 in Hot Standby (mode 3, 547F, 2325 psig), a normal cooldown of Unit 3 was initiated due to a small pressure boundary leak of the Reactor Coolant System (RCS)(EIIS: AB).At 1516 on January 16, 1989, a leak test of the RCS pressure boundry was commenced in accordance with procedure OP 1004.1,"Reactor Coolant System-System Leak Test Following RCS Opening".At approximately 1648 the leak inspection team reported to the control room a leak of approximately 12 drops per minute at incore flux mapping system guide tube J-12.The leakage was emanating from a crack between the guillotine isolation valve and the Reactor Vessel, and was therefore, unisolable

.In addition, weepage was evident from guide tube J-7 and from the high pressure seal at E-5.Technical Specification 3.1.3.a states,"If reactor coolant leakage exists through a fault in the system boundary that cannot be isolated (ex.vessels, piping, valve bodies)the reactor shall be shutdown, and cooldown to cold shutdown shall be initiated within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />." At 1824 the Plant Supervisor-Nuclear instructed the Reactor Control Operator to prepare for RCS cooldown.At 1915 a normal cooldown of the RCS was initiated in accordance with plant procedures.

Unit 3 reached cold shutdown at 1050 on January 17, 1989 without further incident.Following cooldown, all of the Unit 3 guide tubes above the seal table were inspected using liquid penetrant examination (PT).Indications were present in the following guide tubes: J-7, J-12, H-4, M-3, N-12.The weepage from E-5 was originating from a Swagelok fitting located above the guide tube.Following examination of the Unit 3 guide tubes, the Unit 4 guide tubes were examined by PT.Guide tube conduit H-1 contained rounded indications similar to some of those in Unit 3.CAUSE OF THE EVENT Metallurgical examinations were performed on sections of the J-7 and J-12 guide tubes.Based on the results of the evaluations performed, it is concluded that the cracks/indications in the guide tubes were caused by transgranular stress corrosion cracking.The defects initiated from the outer (OD)diameter surface of the tubes and most likely resulted from chloride contamination.

The source of the presumed chloride contamination is not known at this time.The cause of the weepage from the E-5 conduit fitting was not specifically identified.

ANALYSIS The amount of leakage from the guide tubes was very small and well within the capabilities of the normal makeup system.Unit 3 was cooled down in a normal manner without further incident.Based on this, the health and safety of the public was not affected.NRC FORM 388A I94ISI

NAC Form 3ddA (943)FACILITY NAME uI LICENSEE EVENT REPORT (LERI TEXT CONTINUATION OOCKET NUMBEA I?I LER NUMBER Id)APPAOVEO OMB NO.3150WIOO EXPIRES: B/31/EB PAGE I31 U.S, NUCLEAR AFGULATORY COMMISSION Turkey Point Unit 3 TEXT I/Imari ssrooeis nqukrd.Irse sr/I//oorrs//r//IC Famr 3SBA'>>>o 5 o o o 2 5 0 YEAR$E Q I/E N T I A L NI/MSE4 002 REVISION NVMSS4 0 0 3 OF 0 4 Following Unit 3 cooldown, the affected sections of the leaking guide tubes J-7 and J-12 were removed and sent to an offsite materials laboratory for evaluation.

Based on the results of the evaluations it was concluded that indications on the guide tubes were caused by transgranular stress corrosion cracking.,The defects initiated from the OD surface of the tube and most likely resulted from chloride contamination.

Since maintenance activities are performed frequently above the seal table but not below the seal, table, it is believed that the presumed chloride contamination is limited to above the seal table.The evaluations performed also indicated that detection of the defects can be accomplished using PT examinations.

CORRECTIVE ACTIONS 1)Unit 3 was cooled down, and all of the guide tubes were examined by PT.These examinations revealed five guide tubes with unacceptable indications on the tube.2)A plant modification was performed to replace the affected sections of guide tubes J-7 and J-12.3)The indications on guide tubes H-4, M-3 and N-12 were removed with a burr or hand file.Following removal of the indications, wall thickness verifications were performed on the tubes.The areas were then examined by PT to ensure the indications were completely removed.4)The Swagelok fitting at E-5 was disassembled and reworked.The fitting exhibited no leakage when returned to service.5)The Unit 3 guide tubes were verified to be leak free at full pressure.6)The guide tubes above the seal table in Unit 4 were examined by PT.The indications at location H-1 will be removed prior to Unit 4 entering mode 4.7)Plant procedures require that the seal table area be visually inspected for leakage following an opening,and reclosing of the RCS.In addition, FPL will reinspect the guide tubes between the seal table and the high pressure fitting for Unit 3 and 4 using PT.This reinspection will be performed for Unit 4 during the next refueling outage for Unit 4, and for Unit 3 during the next refueling outage for Unit 3.8)9)The guide tubes between the seal table and the high pressure fittings will be cleaned with an appropriate solvent to remove any residual chlorides on the guide tubes.This action will be completed prior to entering mode 4 for Unit 4 and during the next refueling outage for Unit 3.r FPL will attempt to identify the source of the presumed chloride contamination.

Additional corrective actions to prevent recurrence will be taken, as appropriate, depending on the results obtained.NAC FOAM SSSA I9BSI IRC form 388A 9.83)LICENSEE E T REPORT (LER)TEXT CONTINUATI U.S, NUCLEAR REGULATORY COMMISSION APPROVEO OMB NO.3)50M)04 EXPIRES: 8/31/88 FACILITY NAME 11)Turkey Point Unit 3 DOCKET NUMBER)3)YEAR).ER NUMBER)8)ferTO SEOVENTIAL 44iR r/UMBER~i~o.REV/SION ff 4)NUMBER PACE 13)TEXT lll more e>>oe/4 rer/ulred, u>>edd/o'o/ro/

HRC%%drm 3SSA 9/(17)o 5 o o o 2 5 0 9 002-0 0 04OF 4 ADDITIONAL INFORMATION Although Turkey Poi'nt has had RCS leaks in the past, no LER s were identified that describe a similar event.The guide tube material is ASTM A213, 304 SS, cold drawn and heat treated.NRC FORM 388A (9 83)

'4~,1 P.O.Bnx 14000, Juno Seach, FL 33408.0420 FEBRUARY.1 4$98.9 L-89-50 10 CFR 50.73 U.S.Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.20555 Gentlemen:

Re: Turkey Point Unit 3 and 4 Docket Nos.50-250 and 50-251 Reportable Event: 250-89-02 Date of Event: January 16, 1989 Reactor Cooldown Required by Technical Specifications due to Small Unisolable Leak of Reactor Coolant S stem at Seal Table The attached Licensee Event.Report (LER)is being submitted pursuant to the requirements

'f 10 CFR 50.73 to provide notification of the subject event.Very truly yours, Pg~+//~~a Q V W.F.Conw Senior Vic President-Nuclear WFC/RHF/cm Attachment cc: Malcolm L.Ernst, Acting Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant an FPL Group company